Vomiting is a complex motor behavior that requires the coordinated action of musculature within the gastrointestinal and aerodigestive tracts. The mechanisms of airway protection during vomiting have not been studied and are presently unknown. This is in contrast to an extensive body of literature providing information on airway protective mechanisms operational during swallowing. Acute and chronic animal models will be utilized to study the role of the laryngeal, pharyngeal and hyoid muscles during vomiting. Investigation of the associated movements of the tongue base, hyoid bone, cricoid and thyroid cartilage, and epiglottis will also be studied. The action of these aerodigestive muscles will be temporally correlated with the action of the esophagus and gastrointestinal tract, and lower respiratory musculature. Finally, the relative contribution of peripheral reflexes and direct central nervous system control over the motor events that comprise vomiting will be studied.